<!--The content below is only a placeholder and can be replaced.-->
<div style="text-align:center">
  <h1>
    Welcome to {{title}}!
  </h1>
  <h2>---> {{num}}</h2>
  <ul>
    <li *ngFor="let hero of heroes">
      {{hero}}
    </li>
  </ul>
  <button (click)="increment()">加加加</button>
</div>


